Since leisure time is increased by extension of the five-day workweek and people are increasingly interested in escaping from a city, spending leisure time in a natural space, and enjoying camping in the outdoors, various camping products are being released.
In addition, it is important to solve a heating problem in order to enjoy camping regardless of season, and accordingly, products, such as a stove and the like, including a combustion apparatus having various combustion methods are being released.
Among such combustion apparatuses, products employing a combustion apparatus utilizing electricity are convenient to use but since electrical power is not sufficiently supplied at most camping areas, the use of such combustion apparatuses is highly limited.
In addition, products employing combustion apparatuses utilizing gas or petroleum are convenient to use, but gas or petroleum is difficult to easily obtain from surroundings thereof, and such fuel needs to be handled with a lot care. Particularly, in order to be suitably used for camping, such products have to be miniaturized to be conveniently carried, and since flues for discharging carbon monoxide, carbon dioxide, and the like are difficult to implement in such products, there is an inconvenience in that ventilation has to be periodically performed when using them.
Accordingly, various products employing combustion apparatuses utilizing wood fuel, which adds atmosphere of camping and is easy to handle and supply, are being released.
A firewood fuel (wood) combustion apparatus is a typical combustion apparatus utilizing wood fuel.
A prior art related to a firewood fuel combustion apparatus is disclosed in Korean Registered Utility Model No. 20-0452982 (Mar. 22, 2011) “Firewood Stove,” and a firewood stove in the registered utility model includes a body forming a combustion chamber and having a central axis disposed in parallel to the ground, a cap and legs hinge-coupled to the body, an ashtray configured to slide in and out of the body, and a stovepipe mounting hole installed in an upper end of the body.
Since firewood, which is used in the firewood combustion apparatus disclosed in the registered utility model, is easy to burn, a structure of a combustion chamber that discharges combustion gas through a flue is simple and easy to design, thermal output (an amount of heat) generated during combustion is high, and firewood is easy to obtain from surroundings thereof, but since a combustion time of firewood is relatively short, there is a demerit in that firewood fuel has to be frequently input to the combustion apparatus.
In addition, while an importance of utilizing forest bio mass has emerged to address rising oil prices and reduce greenhouse gas, a wood pellet fuel combustion apparatus exists as a different combustion apparatus utilizing wood fuel.
A prior art related to the pellet fuel combustion apparatus is disclosed in Korean Patent Registration No. 10-1306160 (Sep. 3, 2013) “Method of Burning Wood Pellet and Burner,” and the burner in the registered patent is formed in such a way that ceramic particles are laid on a perforated grille to form a grate, wood pellets are sprayed on the perforated grille while combustion air is sprayed from a lower side of the perforated grille, the ceramic particles and the wood pellets on the grate are stirred by a stirring part when ash generated by combustion is discharged to a second combustion space positioned along a lower stream by a stream of the combustion air or gas, and a clinker of a combusted material generated on the grate is broken.
In the pellet fuel combustion apparatus disclosed in the registered patent, since it is easy to discharge combustion gas through a flue similar to a firewood fuel combustion apparatus and combustion fuel is maintained for a long time and heat is stably output when fuel including a plurality of pellets is input one time, the pellet fuel combustion apparatus is convenient to use. However, since fuel to be input is limited to pellet fuel, there are demerits in that since the fuel is difficult to supply from surroundings thereof, the pellet fuel has to be additionally prepared by being purchased for camping.
Accordingly, products that employ a combustion apparatus capable of using both firewood and pellet fuel, and which normally use and combust firewood when a user is active and use and combust pellets when the user is asleep so that a certain thermal power is maintained for a long time, simultaneously realize both strong thermal output and stable thermal output performance for a long time, and so have recently been in the spotlight.
However, such a firewood and pellet combustion apparatus is manufactured in a form in which a pellet combustion chamber is additionally installed in a combustion chamber rather than in a form in which both firewood and a pellet are burned in a common combustion chamber.
That is, since a firewood and pellet combustion apparatus that is currently commercially available is manufactured in a form in which a firewood combustion apparatus and a pellet combustion apparatus are simply coupled to each other instead of in a form of a single combustion apparatus so that using the firewood and pellet combustion apparatus is the same as using two combustion apparatuses, a cost burden for purchasing the firewood and pellet combustion apparatus is high according to an increase in a manufacturing cost of the product, and since a volume of a product employing the firewood and pellet combustion apparatus increases and portability thereof decreases, there is a limitation in that the product employing the firewood and pellet combustion apparatus is not suitable for camping use and the like.
Such a limitation is attributable to difference in combustion environments of firewood and pellet fuel.
More specifically, since air easily circulates for burning firewood, firewood may be burned regardless of a form of a combustion chamber. That is, since air easily circulates between pieces of firewood due to forms of the pieces of firewood, the pieces of firewood are burned as long as air is supplied to the combustion chamber in any direction, and since the forms of the pieces of firewood are not greatly changed even when the pieces of firewood are burned and become charcoal and ash, an air flow is smoothly maintained so that combustion is smoothly performed without being hindered by a direction of a supply of air.
Conversely, since pellets are small and cylindrical and have a constant size and shape and very small gaps are formed between the fuel pellets in a state in which fuel including a plurality of pellets is stored in the combustion chamber, outside air cannot easily reach a pellet fuel thereinside, and since air has to be supplied to the pellet fuel by being quickly supplied to surfaces of pellets which are being combusted, there is a limitation on the direction or position of the supply of air.
Accordingly, since a combustion region of a conventional pellet fuel combustion apparatus is concentrated on a combustion mesh (a crucible) or the like and stable combustion is performed by intensively supplying air to the combustion region while the combustion mesh is maintained at a high temperature, a structure and a form of the combustion chamber should be limited.
That is, in the case of the pellet fuel, stable burning similar to a case of firewood fuel being simply stacked is not secured, and accordingly, since a combustion chamber having a specific structure is required in addition to a combustion chamber for firewood, it is impossible to use both firewood and a pellet at the same time, and since the conventional combustion apparatus for both firewood and pellet fuel has to be manufactured to have a form in which two combustion apparatuses are only simply coupled due to the above-described problems, it is impossible to manufacture a combustion apparatus for both firewood and pellet fuel using a single combustion chamber, and since effects of easing manufacturing and reducing a manufacturing cost are difficult to expect, there is a problem in that a cost burden of a user for purchasing the combustion apparatus is increased.